Support for reflectors.



J. D. CUMMING.

SUPPORT FOR REFLECTOHS.

APPLICATION FILED SEPT. l4. x911.

1,295,701. Patented Feb.25,1919.

' I OFFIE SUPPORT FOR REFLECTORS.

Specification of Letters Patent.

Patented Feb. 25. 1919.

- Application filed September 14. 1917. Serial No. 191.440.

To all who) it may com-rm.

Be it known that I, Janus l)l-IANS CUM- )uxo, of the town of (TopperCliff, in the district of Sudbury. in the l 'rovinee of Ontario, Canada,have invented certain new and useful Improvements in Supports forl'leflectors, of which the following is the specification.

My invention relates to improvements in supports for reflectorsparticularly adaptable to parabolic reflectors and the object of theinvention is to devise simple means --for supporting a reflector so thatit may be adjustably swung around a center coinciding with the focalpoint of the reflector and the center of intensity of a stationar lightsource and it consists essentially of the following arrangement andconstruction of parts as hereinafter more particularly ex plained.

Figure 1, is a perspect ve view oi my support showing a reflectorcarried thereby, the

reflector being in vertical section.

Fig. 2, is a vertical section through Fig. 1 with the major portion ofthe reflect or broken away.

Fig. 3, is a plan view similar to Fig. 2.

In the drawings like letters of reference indicate corresponding partsin the various figures.

1 indicates a burner head provided, with a horizontally extendingtubular portion 1 having a threaded exterior portion at its outer end. 2indicates the burner, which is secured in the tubular portion 1 and fromwhich a horizontally directed flame 2* extends when the burner islighted, the center of intensity of the flame 2* being indicated by across 3.

a indicates a parabolic reflector, which is mounted so that the focalpoint of the reflector coincides with the center of intensity 3 of thelight source represented by the It Will be readily understood that whenusing a reflector or more particularly a parabolic reflector with anylight it is very desirable to keep the center of illumination as nearthe focal point of the reflector as possible. The reason for this isthat to secure a ll'ltlXillllllll illumination the rays of light must bereflected from the surface of the reflector in a beam of parallel rays.

A parabolic reflector from its peculiar shape reflects all rays of lightoriginating at its focal point in such a beam. Sinc the focal point of aparabola is of no'1nagnitude it is apparent that a light of anyappreciable size can not be contained therein and, therefore. perfectreflection can never be obtained. If. however, the center oi in-vtensity of the light or flame be kept as close as possible to the focalpoint of the reflector the maximum etlieiency ot' reflection attainablewill be obtained.

In order to swingably mount the reflector so as to obtain the aboveresult, that is. keep the. center of swing. of the reflector, center oflight source and the focal pointof the reflector coincident I haveprovided the following means for mounting the reflector upon the burner.

5 indicates a gland which is provided with an internal thread, which isscrewed on to the external thread of the tubular portion 1 of theburner. The gland 5 is also provided with an external thread 5". (3 and7 indicate lugs, which extend out from the dian'ietrically oppositesides of: the gland in proximity to its outer end or that end of thegland next to the burner 2. 4 indicates a slot, which is formed in theinner end of the reflector 4 and is vertically disposed. 8 indicates abracket, which is secured to the reflector 4 at each end ot-the slot 1*,such bracket being provided with arms 9. 10, 11 and 12 extendingoutwardly from the cross bars of the bracket.

15 and l6 indicate are-shaped bar po tions, the bar portion being formedintegral with the arms 10 and ll and the bar portion 16 with the arms 9and 12. The bar portions 15 and 16 are arc-shape in form and concentricwith the focal point of the reflector 4' and the center of illuminationoi the flame 2. 17 indicates an internally threaded annular nut. whichis screwed upon the gland i and provided with wings l8 and l!) by whichthe nut is screwed into position.

When it is desired to attach the reflector in position all that it isnecessary to do is to screw the' nut 17 upon the gland 5, the areshapedbar portions 15 and lti being inserted between the nut and thedian'ietrically extending lugs (3 and 7.

Vthen it is desired to adjust. the angle of the reflector 4- all that itis necessary to do is to loosen the nut 17 and swingthe reflector to thedesired position. As the arc-shaped portions 15 and it; are concentricwith the eenter of light source formed by the flame 2", Whichcorresponds also to the focal point of the reflector, the center ofintensity of illuminationalways coincides with such focal point at anyposition to which the reflector is swung.

With a reflector, which is rigidly fixed to the source of light, it hasalways been necessary to swing both the reflector and source of light tochange the direction of the light rays. By my'refiector holding devicethe direction of the rays of light may be changed without moving thesource of light or removing the center of intensity of the light fromthe focal point of the reflector.

Although I have describerlany invention as particularly adaptable to aparabolic reflector it will, of course, be understood that it may beused with any other type which does not throw parallel rays of light,the

'bbject being no matter what type of reflector is used that when thereflector is swung so as to direct the beams of light at any desiredangle that the center of swing of such reflector coincides with thecenter of illumination.

It will be understood that the arc-shaped bars 15 and 16 are so disposedas to form sectors, the centers of which are located at each side of thecenter of illumination sothat the line joining these centers would passthrough the center of illumination. By forming the slot 4* as abovedescribed the flame 2 passes horizontally from the burner through. theback of the reflector into the interior thereof, the slot being of suchdimensions thatthe flame passes therethro'ugh no 1 matter at whatangular position the reflector is set within the limits desired and sothat the center of the flame coincides with the focal point of thereflector.

What I claim as my invention is:

1. The combination with the burner arm, of a parabolic reflector havingan arc-shaped vertically disposed slot in the back thereof, arc-shapedbar portions concentric with the focal point of the reflector andcarried by 45 the reflector and clamping means carried by the burner arm(lQSlgIlQd to engage each inner and outer edge of the bar portions tosecure them in position.

2. The combination with the burner arm, of a parabolic reflector havingan arc-shaped vertically disposed slot in the back thereof, arc-shapedbar portions concentric with the focal point of the reflector andcarried by the reflector, a member carried by the burner arm havingradially extending lugs adapted to extend against the inner edge of theareshaped bars, and a clamping screw designed to bear against the outeredge of the areshaped bars.

Witness: 7

G. E. BUCHANAN.

